Weird Nature
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14 Bizarre Female Reproductive Systems In The Animal Kingdom

Updated September 23, 2021 265k views14 items
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Animal reproductive systems and practices can be incredibly complex - often more complicated than our own human mating rituals and reproductive cycles. Most research in the animal sciences field focuses on male genitalia and sex habits. Researchers found that of 364 published research papers, only 8% focused on female animals and their genitalia. 

However, sexism might not be the definitive reason for this gender gap. Due to their internal nature, vaginas are inherently more difficult to study than penises. Even with such little research, the things we do know about the vaginas of the animal kingdom are incredibly interesting. Hopefully, in the future, the scientific community will put an equal amount of research focus on female reproductive systems in the animal world - because there are some interesting ones out there.

  • Some Sharks Carry Cannibalistic Fetuses In Their Womb

    Most fish species are born by emerging from an egg, but some species of shark are unique in that they give birth to live young. Sand tiger sharks are among those, and what goes on inside their wombs is competitive cannibalism. 

    Female sand tiger sharks can gestate up to 12 pups at once, but only two will emerge alive. The rest are consumed by the largest and most aggressive pups, ensuring the fittest possible sharks are born. Sand tiger sharks are able to mate with multiple males at once, so this contest of fratricide may be an evolutionary adaptation to ensure the dominance of one male's genes over the other. More often than not, the remaining two pups have the same father. 

  • Female Ceratioid Anglerfish Physically Fuse With Males

    Photo: Meocrisis / Wikimedia Commons / CC BY-SA 3.0

    These deep sea creatures are most well known for the seductive, glowing lures on the top of their heads, which they use to attract prey in the darkness. Only the females have these lures, and they are much larger than their male counterparts. 

    Ceratioid anglerfish (Angler fish belonging to the suborder Ceratioidei) are unique in comparison to other angler fish. They demonstrate extreme sexual dimorphism—females are much larger than males. Once they emerge from eggs, males are incapable of hunting on their own, wandering the ocean until they find a female through sight or scent. A male then attaches himself to the female and, over time, the male and female tissues and circulatory systems fuse. The male becomes dependent on the female for blood-transported nutrients in order to survive. A single female can carry up to seven males on her body at once. When the female is ready to reproduce, both she and the males excrete reproductive material (eggs and sperm) into the surrounding water, enabling external fertilization to occur. 

  • A Drone's Endophallus Breaks Off Inside A Queen Bee's Vagina

    Bees have very complex social structures that allow them to work efficiently in large communities. Every beehive has a queen, which determines most of the activity of a colony. She is typically the mother of the entire hive, and she’s in total control over the reproductive process. She can release a pheromone designed to suppress the fertility of every other female in the entire colony.

    Shortly after a new queen is born, she embarks on a frenzied sexual escapade. Scientists don't yet know how she knows this, but she flies to a location where drones, or male bees, gather each day, year after year, called a "drone congregation area." There, she mates with as many as 20 males midair. The males use their endophallus to inject sperm into the queen's vagina, an action that causes the endophallus to detach and the drones to die soon thereafter. She collects all the sperm she needs for the rest of her life in one or two mating flights, resulting in many new generations of bees.

  • The Common Tenrec Can Give Birth To 32 Babies At Once

    These relatively small Madagascar and Comoro Island natives, known as the common tenrec, hold the distinction of bearing the largest litter of any mammal, despite their small stature.

    In the wild they have been known to carry up to 16 embryos at a time, but in captivity that number can be as high as 32. This feat is even more impressive given their relatively small size. With all those babies, it’s no surprise that tenrecs also have the most nipples of any animal. Some have been recorded with up to 29 nipples. Unlike most mammals, the tenrec does not have a vagina, but a multipurpose cloaca similar to that of birds.